Light-emitting device

ABSTRACT

It is an object of the present invention to provide a light-emitting device where periphery deterioration can be prevented from occurring even when an organic insulating film is used as an insulating film for the light-emitting device. In addition, it is an object of the present invention to provide a light-emitting device where reliability for a long period of time can be improved. A structure of an inorganic film, an organic film, and an inorganic film is not continuously provided from under a sealing material under a cathode for a light-emitting element. In addition, penetration of water is suppressed by defining the shape of the inorganic film that is formed over the organic film even when a structure of an inorganic film, an organic film, and an inorganic film is continuously provided under a cathode for a light-emitting element.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a light-emitting device manufactured byusing an element (light-emitting element) that emits light by applying acurrent between electrodes with a luminescent material therebetween, andmore particularly, relates to a sealing structure in the light-emittingdevice.

2. Description of the Related Art

In recent years, thin and light displays using light-emitting elementshave been actively developed. In order to manufacture a light-emittingelement, a material that produces luminescence by applying a current isinterposed between a pair of electrodes. Since the light-emittingelement itself emits light unlike a liquid crystal, a light source suchas a backlight is not necessary, and thus, the element itself is quitethin. Accordingly, the light-emitting element is quite advantageous whenthin and light displays are manufactured.

However, one of the backgrounds to the fact that no practicalapplication has been achieved in spite of having these great advantagesis a problem of reliability. A light-emitting element using an organicmaterial is often deteriorated due to moisture (water), and has thedisadvantage that it is hard to obtain reliability for a long period oftime. The light-emitting element deteriorated due to water causesdecrease in luminance or emits no light any longer. This is consideredto be a cause for a dark spot (black spot) or luminance degradation fromthe periphery of a light-emitting device (luminance degradation in whicha light-emitting area gradually decreases from an edge portion of adisplay device, which is hereinafter referred to as “peripherydeterioration”) in a light-emitting device using a light-emittingelement, and various measures has been proposed in order to suppressthis deterioration (for example, refer Patent Documents 1 and 2).

However, even if these measures are applied, sufficient reliability hasnot been obtained yet, and further improvement in reliability has beendesired.

In addition, for a light-emitting device, it is often the case that anorganic insulating film that can be formed by coating is used as aninsulating film. This organic insulating film has properties that arequite favorable in applying to a light-emitting device, such assuperiority in flatness and capability to reduce unevenness of theunderlying layer.

Patent Document 1:

Japanese Patent Application Laid-Open No. 9-148066

Patent Document 2:

Japanese Patent Application Laid-Open No. 7-169567

SUMMARY OF THE INVENTION

The organic insulating film has the properties, which are quitefavorable when a light-emitting device is formed. However, in the caseof a light-emitting device that has an interlayer insulating film formedwith the use of an organic insulating film, periphery deterioration canbe accelerated depending on the structure thereof.

Consequently, it is an object of the present invention to provide alight-emitting device where deterioration at the periphery can beprevented from occurring even when an organic insulating film is used asan insulating film for the light-emitting device. In addition, it is anobject of the present invention to provide a light-emitting device wherereliability for a long period of time can be improved.

One of structures of a light-emitting device according to the presentinvention for solving the problem includes a first substrate; a firstinsulating film comprising organic material, formed over the firstsubstrate; a film comprising inorganic material formed on the firstorganic insulating film; a second insulating film covering an edge ofthe film comprising inorganic material, formed over the first insulatingfilm; a light emitting element having at least one electrode, a portionof the electrode formed on the second insulating film; and a secondsubstrate opposed to the first substrate with a sealing materialinterposed therebetween, wherein the sealing material is formed on aportion of the film comprising inorganic material, wherein the filmcomprising inorganic material is not overlapped with the electrode, andwherein there is a gap between the sealing material and the electrode.

One of the structures of the light-emitting device according to thepresent invention for solving the problem includes a first substrate; afirst insulating film comprising organic material, formed over the firstsubstrate; first and second films formed on the first organic insulatingfilm, each of the first and second films comprising inorganic material;a second insulating film comprising organic material, covering thesecond film and comprising inorganic material and an edge of the firstfilm comprising inorganic material, formed over the first insulatingfilm; a light emitting element having at least one electrode, a portionof the electrode formed on the second insulating film; and a secondsubstrate opposed to the first substrate with a sealing materialinterposed therebetween, wherein the sealing material is formed on aportion of the first film comprising inorganic material, wherein aportion of the second film comprising inorganic material is overlappedwith the electrode, and wherein there are a gap between the first filmcomprising inorganic material and the second film comprising inorganicmaterial and a gap between the sealing material and the electrode.

One of the structures of the light-emitting device according to thepresent invention for solving the problem includes a first substrate; afirst insulating film comprising organic material, formed over the firstsubstrate; at least first and second films formed on the firstinsulating film, each of the first and second films comprising inorganicmaterial; a second insulating film comprising organic material, coveringan edge of the first film comprising inorganic material and an edge ofthe second film comprising inorganic material, formed over the firstinsulating film; a light emitting element having at least one electrode,a portion of the electrode formed on the second insulating film; and asecond substrate opposed to the first substrate with a sealing materialinterposed therebetween, wherein each of the first film comprisinginorganic material and second film comprising inorganic material has aportion of less than 1 mm in width between an edge of the firstsubstrate and the electrode, and wherein there is a gap between thesealing material and the electrode.

One of the structures of the light-emitting device according to thepresent invention for solving the problem includes a first substrate; afirst insulating film comprising organic material, formed over the firstsubstrate; at least first and second films formed on the firstinsulating film, each of the first and second films comprising inorganicmaterial; a second insulating film comprising organic material, coveringan edge of the first film comprising inorganic material and an edge ofthe second film comprising inorganic material, formed over the firstinsulating film; a light emitting element having at least one electrode,a portion of the electrode formed on the second insulating film; and asecond substrate opposed to the first substrate with a sealing materialinterposed therebetween, wherein each of the first film comprisinginorganic material and second inorganic film comprising inorganicmaterial has a portion of less than 1 mm in width between an edge of thefirst substrate and the electrode, and

wherein the sealing material is overlapped with the electrode and theoverlap is 15 μm or less.

One of the structures of the light-emitting device according to thepresent invention for solving the problem includes a first substrate; afirst insulating film comprising organic material, formed over the firstsubstrate; at least first and second films adjacent to each other formedon the first insulating film, each of the first and second filmscomprising inorganic material; a second insulating film comprisingorganic material, covering an edge of the first film comprisinginorganic material and an edge of the second film comprising inorganicmaterial, formed over the first insulating film; a light emittingelement having at least one electrode, a portion of the electrode formedon the second insulating film; and a second substrate opposed to thefirst substrate with a sealing material interposed therebetween, whereineach of the first and second films has a portion of less than 1 mm inwidth, wherein a distance between the first film comprising inorganicmaterial and second film comprising inorganic material is 5 μm or more,and wherein there is a gap between the sealing material and theelectrode.

One of the structures of the light-emitting device according to thepresent invention for solving the problem includes a first substrate; afirst insulating film comprising organic material, formed over the firstsubstrate; at least first and second films adjacent to each other formedon the first insulating film, each of the first and second filmscomprising inorganic material; a second insulating film comprisingorganic material, covering an edge of the first film comprisinginorganic material and an edge of the second film comprising inorganicmaterial, formed over the first insulating film; a light emittingelement having at least one electrode, a portion of the electrode formedon the second insulating film; and a second substrate opposed to thefirst substrate with a sealing material interposed therebetween, whereineach of the first film comprising inorganic material and second filmcomprising inorganic material has a portion of less than 1 mm in width,wherein a distance between the first film comprising inorganic materialand second film comprising inorganic material is 5 or more, and whereinthe sealing material is overlapped with the electrode and the overlap is15 μm or less.

One of the structures of the light-emitting device according to thepresent invention for solving the problem includes a first substrate; afirst insulating film comprising organic material, formed over the firstsubstrate; a film comprising inorganic material formed on the firstinsulating film; a second insulating film comprising organic material,covering an edge of the film comprising inorganic material, formed overthe first insulating film; a light emitting element having at least oneelectrode, a portion of the electrode formed on the second insulatingfilm; and a second substrate opposed to the first substrate with asealing material interposed therebetween, wherein the film comprisinginorganic material has at least first and second openings at leastbetween an edge of the first substrate and the electrode, wherein thefirst and second openings are arranged adjacent to each other in anarrower-side direction of the first and second openings, wherein eachwidth of the first and second opening is 5 μm or more in theshorter-side direction of the first and second openings, wherein adistance between the first and second openings is less than 1 mm, andwherein there is a gap between the sealing material and the electrode.

One of the structures of the light-emitting device according to thepresent invention for solving the problem includes a first substrate; afirst insulating film comprising organic material, formed over the firstsubstrate; a film comprising inorganic material formed on the firstinsulating film; a second insulating film comprising organic material,covering an edge of the film comprising inorganic material, formed overthe first insulating film; a light emitting element having at least oneelectrode, a portion of the electrode formed on the second insulatingfilm; and a second substrate opposed to the first substrate with asealing material interposed therebetween, wherein the film comprisinginorganic material has at least first and second openings at leastbetween an edge of the first substrate and the electrode, wherein thefirst and second openings are arranged adjacent to each other in anarrower-side direction of the first and second openings, wherein eachwidth of the first and second opening is 5 μm or more in theshorter-side direction of the first and second openings, wherein adistance between the first and second openings is less than 1 mm, andwherein the sealing material is overlapped with the electrode and theoverlap is 15 μm or less.

The present invention can be applied to not only a light emitting devicebut also a semiconductor device. One of the structures of asemiconductor device according to the present invention for solving theproblem includes a first substrate; a first insulating film comprisingorganic material, formed over the first substrate; a film comprisinginorganic material formed on the first organic insulating film; a secondinsulating film covering an edge of the film comprising inorganicmaterial, formed over the first insulating film; an electrode, a portionof the electrode formed on the second insulating film; and a secondsubstrate opposed to the first substrate with a sealing materialinterposed therebetween, wherein the sealing material is formed on aportion of the film comprising inorganic material, wherein the filmcomprising inorganic material is not overlapped with the electrode, andwherein there is a gap between the sealing material and the electrode.

In addition, there are not so many wirings dragged from the outside ofor from under a sealing material close to an upper electrode for alight-emitting element in the case of an actual active matrix panel.However, such a structure can be required to be formed, anddeterioration occurs naturally from that part. The commercial value of alight-emitting device in which a periphery portion is not lighted due todeterioration is dramatically decreased even though the portion is justa part of the light-emitting device. Therefore, the structure accordingto the present invention can be preferably used also as a measure for asmall portion at the periphery of a light-emitting element.

The light-emitting device according to the present invention, which hasthe structure described above, is a light-emitting device whereperiphery deterioration can be prevented from occurring even when anorganic insulating film is used as an insulating film, and is also alight-emitting device where reliability for a long period of time can beimproved.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains drawings executed in color.Copies of this patent or patent application publication with colordrawings will be provided by the Office upon request and payment of thenecessary fee.

In the accompanying drawings:

FIGS. 1A and 1B are diagrams showing examples of structures of alight-emitting device according to the present invention;

FIGS. 2A to 2C are diagrams showing one example of the structures of alight-emitting device according to the present invention;

FIGS. 3A to 3C are diagrams showing one example of the structures of alight-emitting device according to the present invention;

FIGS. 4A to 4C are diagrams showing one example of the structures of alight-emitting device according to the present invention;

FIGS. 5A to 5C are diagrams showing one example of the structures of alight-emitting device according to the present invention;

FIGS. 6A to 6C are diagrams showing one example of the structures of alight-emitting device according to the present invention;

FIGS. 7A and 7B are diagrams showing one example of the structures of alight-emitting device according to the present invention;

FIGS. 8A to 8D are diagrams illustrating a method for manufacturing alight-emitting device according to the present invention;

FIGS. 9A to 9C are diagrams illustrating the method for manufacturing alight-emitting device according to the present invention;

FIG. 10 is a top view of a light-emitting device according to thepresent invention;

FIGS. 11A to 11E are diagrams showing examples of electronic devicesaccording to the present invention;

FIGS. 12A and 12B are experimental results relating to a light-emittingdevice that has the structure in Embodiment Mode 1;

FIGS. 13A to 13D are experimental results relating to a light-emittingdevice that has the structure in Embodiment Mode 2;

FIGS. 14A to 14E are experimental results relating to a light-emittingdevice that has the structure in Embodiment Mode 3;

FIGS. 15A to 15D are experimental results relating to a light-emittingdevice that has the structure in Embodiment Mode 4;

FIGS. 16A and 16B are experimental results relating to a light-emittingdevice that has the structures in Embodiment Modes 2 and 5; and

FIG. 17 is a schematic view of the light-emitting device that has thestructures in Embodiment Modes 2 and 5.

DETAILED DESCRIPTION OF THE INVENTION

Embodiment Modes of the present invention will be described below.However, the present invention may be embodied in a lot of differentforms, and it is to be easily understood that various changes andmodifications will be apparent to those skilled in the art unless suchchanges and modifications depart from the scope of the presentinvention. Therefore, the present invention is not to be construed withlimitation to what is described in the embodiment modes.

The inventors has found out that penetration of water from the outsideatmosphere of the light emitting device is accelerated when an organicfilm sandwiched in contact with inorganic films (a laminated structureof an inorganic film, an organic film, and an inorganic film) is exposedto the outside atmosphere of the light emitting device.

In the case of a light-emitting device, the inorganic films correspondto a substrate, an opposed substrate, a wiring a passivation film, anelectrode, and the like. When an insulating film is formed with the useof an organic material to have a structure in which the organic film issandwiched in contact with any of the inorganic films described above,penetration of water from the outside atmosphere of the light emittingdevice is accelerated through the insulating film comprising organicmaterial, and periphery deterioration thus proceeds. Although the reasonof this phenomenon has not been clearly figured out, the inventorssuspect that the surface tension between the organic film and theinorganic film is involved.

In the case of a light-emitting device, an electrode for alight-emitting element is nearly always formed by using an inorganicfilm. Therefore, a light-emitting device basically has a laminatedstructure of a substrate (inorganic), an insulating film or alight-emitting laminated body (organic), and an electrode (inorganic),and water under the electrode promptly reaches a light-emittinglaminated body due to this laminated structure so that deterioration ofthe light-emitting laminated body is accelerated. Therefore, it isimportant as a measure to make it harder for water to reach under theelectrode.

The present invention provides a light-emitting device including a firstorganic film formed in contact with a first insulating inorganic film(for example, a substrate), a second inorganic film (for example, awiring or a passivation film) formed in contact with the first organicfilm, and a second organic film formed on the first organic film and thesecond inorganic film, where there are a gap between a third inorganicfilm that is an upper electrode for a light-emitting element, a portionof the third inorganic film being formed in contact with the secondorganic film, and the second inorganic film and a gap between the thirdinorganic film and a sealing material that is a third organic film forattaching an opposed substrate that is a fourth inorganic film when seenfrom the substrate side.

In the light-emitting device according to the present invention, whichhas the structure described above, the second inorganic film is notlocated under the third inorganic film, and the second organic film isthus exposed to the atmosphere within the light-emitting device withouthaving contact with the second and third inorganic films at the gapbetween the second inorganic film and the third inorganic film.Therefore, even when water moves fast in the first organic filmsandwiched between the first inorganic film and the second inorganicfilm, further penetration of water is so difficult at the gap thatperiphery deterioration due to water can be suppressed.

In addition, since the sealing material includes an organic material andhas contact with the opposed substrate that is the fourth inorganicfilm, a structure in which an organic film is sandwiched betweeninorganic films is certainly formed when there is an inorganic filmunder the sealing material. Therefore, when seen from the substrateside, the gap between the sealing material and the third inorganic filmthat is the upper electrode for the light-emitting element is needed.

Further, the present invention provides a light-emitting deviceincluding a first organic film formed in contact with a first insulatinginorganic film (for example, a substrate), a second inorganic film and afifth in organic film (for example, wirings or passivation films) formedin contact with the first organic film, and a second organic film formedon the first organic film and the second and fifth inorganic films, athird inorganic film that is an upper electrode for a light-emittingelement, a portion of the third inorganic film being formed in contactwith the second organic film, and a sealing material that is a thirdorganic film for attaching an opposed substrate that is a fourthinorganic film, where there are a gap between the second inorganic filmand the fifth inorganic film and a gap between the third inorganic filmand the sealing material when seen from the substrate side. In addition,the gap between the second inorganic film and the fifth inorganic filmis positioned in a portion between the sealing material and the thirdinorganic film. The sealing material and the third inorganic film may beoverlapped with a portion of the gap between the second inorganic filmand the fifth inorganic film. However, the sealing material or the thirdorganic film is not allowed to overlap with the gap entirely. It ispreferable that the gap between the second inorganic film and the fifthinorganic film be 5 μm or more, preferably 10 μm or more, and morepreferably 20 μm or more.

In the light-emitting device according to the present invention, whichhas the structure described above, there is the gap between the secondinorganic film and the fifth inorganic film, and the second organic filmis thus exposed to the atmosphere within the light-emitting devicewithout contact with any inorganic film at the gap. Therefore, even whenwater moves fast in the first organic film sandwiched between the firstinorganic film and the second inorganic film, water is held back at thegap, further penetration of water is difficult, and thus, peripherydeterioration due to water can be suppressed. In addition, in thisstructure, water can be held back at the gap even when the fifthinorganic film is overlapped with the third inorganic film. Therefore,penetration of water into a light-emitting laminated body is sodifficult that periphery deterioration can be suppressed.

In addition, since the sealing material includes an organic material andhas contact with the opposed substrate that is the fourth inorganicfilm, a structure in which an organic film is sandwiched betweeninorganic films is certainly formed when there is an inorganic filmunder the sealing material. Therefore, when seen from the substrateside, the gap between the sealing material and the third inorganic filmthat is the upper electrode for the light-emitting element is needed.

Further, the present invention provides a light-emitting deviceincluding a first organic film formed in contact with a first insulatinginorganic film (for example, a substrate), a second inorganic film (forexample, a wiring or a passivation film) formed in contact with thefirst organic film, and a second organic film formed on the firstorganic film and the second inorganic film, a third inorganic film thatis an upper electrode for a light-emitting element, a portion of thethird inorganic film being formed in contact with the second organicfilm, and a sealing material that is a third organic film for attachingan opposed substrate that is a fourth inorganic film, where the secondinorganic film has a portion that is less than 1 mm in width. Inaddition, in the light-emitting device, a distance where the thirdinorganic film is overlapped with the sealing material is 15 μm or less,or there is a gap between the third inorganic film and the sealingmaterial.

In the light-emitting device, which has the structure described above,since the second inorganic film has the thin portion that is less than 1mm in width, penetration of water is suppressed at the portion even whenthe first organic film is sandwiched between the first inorganic filmand the second inorganic film. Therefore, even when the first organicfilm is exposed to the outside atmosphere of the light emitting deviceand the second inorganic film is overlapped with the third inorganicfilm, periphery deterioration can be suppressed.

In addition, since the sealing material includes an organic material andhas contact with the opposed substrate that is the fourth inorganicfilm, a structure in which an organic film is sandwiched betweeninorganic films is certainly formed when there is an in organic filmunder the sealing material. For example, even in the case of a structurein which there is the first organic film on the first inorganic film,there is the second organic film thereon in contact with the firstorganic film, the sealing material is further formed thereon, and thefourth inorganic film is attached, penetration of water is considered tobe accelerated. Therefore, when seen from the substrate side, the gapbetween the sealing material and the third inorganic film that is theupper electrode for the light-emitting element is needed.

Further, the present invention provides a light-emitting deviceincluding a first organic film formed in contact with a first insulatinginorganic film (for example, a substrate), a second inorganic film (forexample, a wiring or a passivation film) formed in contact with thefirst organic film, and a second organic film formed on the firstorganic film and the second inorganic film, a third inorganic film thatis an upper electrode for a light-emitting element, a portion of thethird inorganic film being formed in contact with the second organicfilm, and a sealing material that is a third organic film for attachingan opposed substrate that is a fourth inorganic film, where the secondinorganic film has a plurality of openings each of which has the widthof 5 or more in a narrower-side direction thereof between the thirdinorganic film and an edge of the substrate, the openings are arrangedadjacent to each other in the narrower-side direction of the opening,and a distance between the adjacent openings is less than 1 mm. Inaddition, in the light-emitting device, a distance where the thirdinorganic film is overlapped with the sealing material is 15 μm or less,or there is a gap between the third inorganic film and the sealingmaterial.

In the light-emitting device, which has the structure described above,since each of the openings have the width of 1 μm or more, preferably 5μm or more in the narrower-side direction of the opening, the surfacetension between the organic film and the inorganic film is reduced, andpenetration of water is not accelerated even when the first organic filmis sandwiched between the first inorganic film and the second inorganicfilm. Therefore, even when the first organic film is exposed to theoutside atmosphere of the light emitting device and the second inorganicfilm is overlapped with the third inorganic film, peripherydeterioration can be suppressed.

In addition, since the sealing material includes an organic material andhas contact with the opposed substrate that is the fourth inorganicfilm, a structure in which an organic film is sandwiched betweeninorganic films is certainly formed when there is an in organic filmunder the sealing material. For example, even in the case of a structurein which there is the first organic film on the first inorganic film,there is the second organic film thereon in contact with the firstorganic film, the sealing material is further formed thereon, and thefourth inorganic film is attached, penetration of water is considered tobe accelerated. Therefore, it is necessary that a distance where thesealing material is overlapped with the third inorganic film that is theupper electrode for the light-emitting element be 15 μm or less, orthere be the gap between the sealing material and the third inorganicfilm.

Some modes for carrying out the present invention will be described withreference to with the accompanying drawings. It is to be noted that,when the description of a drawing refers to another drawing, thedescription of the referred-to drawing is applied except the differencebetween the two drawings.

In addition, there are not so many wirings dragged from the outside ofor from under a sealing material close to an upper electrode for alight-emitting element in the case of an actual active matrix panel.However, such a structure can be required to be formed, anddeterioration occurs naturally due to the structure. The commercialvalue of a light-emitting device in which a periphery portion is notlighted due to deterioration is dramatically decreased even though theportion is just a part of the light-emitting device. Therefore, thestructure according to the present invention can be preferably used alsoas a measure for a small portion at the periphery of a light-emittingdevice.

Embodiment Mode 1

FIG. 1A is a cross-sectional view showing a cross section of alight-emitting device according to the present invention. A baseinsulating film 101 is formed on a substrate 100, and a first organicinsulating film 102 is formed thereon. On the first organic insulatingfilm 102, a wiring 103 is formed in contact with the first organicinsulating film 102. Also on the first organic insulating film 102, alower electrode 104 for a light-emitting element is provided, and asecond organic insulating film 105 is formed to cover an edge portion ofthe lower electrode 104. In addition, a light-emitting laminated body106 is provided continuously to cover the second organic insulating film105 and an exposed portion of the lower electrode 104. Further, an upperelectrode 107 for the light-emitting element is provided to cover thelight-emitting laminated body 106. The substrate 100 over which the baseinsulating film 101, the first organic insulating film 102, the wiring103, the lower electrode 104 for the light-emitting element, the secondorganic insulating film 105, the light-emitting laminated body 106, andthe upper electrode 107 for the light-emitting element are formedattached to an opposed substrate 109 with a sealing material 108.

Further, there is a gap a between an edge of the upper electrode 107 forthe light-emitting element and an edge of the wiring 103 extending fromthe outside of sealing material 108 in the direction parallel with thesubstrate. The edge of the wiring 103 is not overlapped with the edge ofthe upper electrode 107. In addition, there is also a gap between thesealing material 108 and the upper electrode 107. It is to be noted thatthe same can be said also when the wiring 103 is not projecting from thesealing material 108.

As materials for the substrate 100 and the opposed substrate 109,inorganic substances such as quartz and organic substances such asplastics (for example, polyimide, acrylic, polyethyleneterephtalate,polycarbonate, polyacrylate, and polyethersulfone) can be used. Thesesubstrates may be used after polishing such as CMP if necessary. In thepresent embodiment mode, glass substrates are used. It is to be notedthat the substrate 100 is treated as an organic material when a plasticsubstrate is used in the present invention.

The base insulating film 101 is provided for preventing diffusions ofmetals such as an alkali metal or an alkali-earth metal in the substrate100, which have a possibility of having a bad influence by diffusing. Asa material for the base insulating film 101, insulating inorganicsubstances such as silicon oxide, silicon nitride, silicon oxidecontaining nitride, and silicon nitride containing oxygen can be used.In the present embodiment mode, the base insulating film 101 is formedby using silicon nitride. Although the base insulating film 101 isformed by a single layer in the present embodiment mode, a multilayer oftwo or more layers may be employed. Alternatively, it is not necessaryto provide the base insulating film 101 when diffusions of impuritiesfrom the substrate are negligible.

The first organic insulating film 102 is formed by using an organicinsulating material such as acrylic or polyimide, a material that has aframe structure formed by a bond of silicon and oxygen and has one orboth of an organic group including at least hydrogen (for example, analkyl group or an aryl group) and a fluoro group as substituents,so-called siloxane, or the like. In particular, a self-flatnessinsulating film that can be formed by coating can reduce unevenness ofthe underlying layer, and can be preferably used for a light-emittingdevice.

The wiring 103 can be formed by using an inorganic substance such as ametal film of conductive aluminum, copper, or the like, and may haveeither a single layer or a multilayer.

The lower electrode 104 and upper electrode 107 for the light-emittingelement is formed by using a material that makes it possible for thelight-emitting laminated body 106 to emit light by applying a highervoltage to one of the lower electrode 104 and the upper electrode 107. Alight-transmitting conductive film is used as the electrode to whichlight generated in the light-emitting laminated body 106 is emitted, forwhich oxides as typified by ITO (indium tin oxide) are known. Inaddition, ITO containing silicon (ITSO), IZO (indium zinc oxide) ofindium oxide mixed with 2 to 20% zinc oxide (ZnO), zinc oxide, GZO(Gallium Zinc Oxide) of zinc oxide containing gallium, and the like canbe used for the light-emitting conductive film, and an ultrathin metalfilm made thinner to have a light-transmitting property can be alsoused.

As for other electrode materials, gold (Au), platinum (Pt), nickel (Ni),tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co),copper (Cu), palladium (Pd), or a nitride of a metal material (TiN) isused for the electrode to which a higher potential is mainly applied.The other electrode can be formed with the use of an alkali metal suchas lithium (Li) or cesium (Cs), an alkali-earth metal such as magnesium(Mg), calcium (Ca) or strontium (Sr), an alloy (Mg:Ag or Al:Li) or acompound (LiF, CsF, or CaF₂) including the alkali metal or thealkali-earth metal, or a transition metal such as a rare-earth metal,and a lamination layer of the alkali, alkali-earth, transition metal anda metal such as aluminum (Al), silver (Ag), or ITO can also be used toform the other electrode.

For the sealing material 108, it is preferable to use an ultravioletcurable resin or the like. In the sealing material 108, a desiccant orparticles for keeping the gap between the substrates constant may bemixed.

In the light-emitting device according to the present invention, whichhas this structure described above in at least a portion of a peripheryportion of the light-emitting device, a laminated structure of aninorganic film, an organic film, and an inorganic film is eliminated atthe gap a, and the existence of the gap a makes coming water held backand makes it possible to suppress progression of periphery deteriorationin the portion that has the structure. Although it is preferable thatthe structure as in the present embodiment mode be provided around theperiphery of the light-emitting device, only a portion of the peripherymay have the structure, and it becomes possible to suppress peripherydeterioration from the portion that has this structure. In addition, thelight-emitting device according to the present invention, which has thisstructure, is a light-emitting device where reliability for a longperiod of time can be improved.

Further, the sealing material 108 is also an organic film, and issandwiched in contact with the opposed substrate 109 and the wiring 103.Since the sealing material 108 is exposed to the outside atmosphere ofthe light emitting device, the light-emitting device is made to have astructure into which water easily comes. However, peripherydeterioration is not accelerated since no more organic film issandwiched in contact with the wiring 103 and the opposed substrate 109,which is an inorganic film, at the inside of the sealing material 108,that is, the region surrounded by the sealing materials.

In addition, there are not so many wirings dragged from the outside ofor from under a sealing material close to an upper electrode for alight-emitting element in the case of an actual active matrix panel.However, such a structure can be required to be formed, anddeterioration occurs naturally from that part. The commercial value of alight-emitting device in which a periphery portion is not lighted due todeterioration is dramatically decreased even though the portion is justa part of the light-emitting device. Therefore, the structure accordingto the present invention can be preferably used also as a measure for asmall portion at the periphery of a light-emitting element.

It is to be noted that it is preferable to provide a desiccant in aregion surrounded by the sealing materials. A desiccant can be providedby being attached to the inside of a concave portion formed for theopposed substrate 109. Providing a desiccant makes it possible tosuppress deterioration for a longer period of time.

Embodiment Mode 2

FIG. 1B shows one of structures of a light-emitting device according tothe present invention. For the same components as those in FIG. 1A, thesame reference numerals and the same materials can be used. In addition,refer to the description for FIG. 1A since a repeated description isomitted.

FIG. 1B is different from FIG. 1A in the structure of the wiring 103shown in FIG. 1A. In FIG. 1B, two wirings of wirings 103 a and 103 b areformed. The wirings 103 a and 103 b have the same material and structureas those of the wiring 103, a portion of the wiring 103 a is exposedoutside a sealing material 108, a gap b is provided between the wirings103 a and 103 b. The gap b may be provided in a portion between thesealing material 108 and an upper electrode 107 for a light-emittingelement. Any of the sealing material 108 and the upper electrode 107 maybe overlapped with a portion of the gap b, but is not allowed to beoverlapped with all of the gap b. In addition, it is preferable that thewidth of the gap b be 5 or more, preferably 10 μm or more, and morepreferably 20 μm or more.

In the light-emitting device according to the present invention, whichhas the structure described above, a first organic insulating film 102is formed between the base insulating film 101 and the wiring 103 a tobe in contact with the both. Since the first organic insulating film 102is exposed to the outside atmosphere of the light emitting device, watercomes into the first organic insulating film 102 at a fat speed.However, a laminated structure in which an inorganic substance, anorganic substance, and an inorganic substance are laminated in order,into which water comes easily, is not formed at the gap b. Therefore, itis difficult for water at an edge of the wiring 103 a to come furtherinto the inside so that periphery deterioration can be suppressed. It isto be noted that the same can be said also when the wiring 103 a is notformed outside the sealing material 108 and the edge at the periphery ofthe light-emitting device is covered with the sealing material 108.

In addition, when this structure is employed, periphery deteriorationcan be suppressed even though the wiring 103 b is formed also under theupper electrode for the light-emitting element.

Although it is preferable that the structure as in the presentembodiment mode be provided around the periphery of the light-emittingdevice, only a portion of the periphery may have the structure, and itbecomes possible to suppress periphery deterioration from the portionthat has this structure. In addition, the light-emitting deviceaccording to the present invention, which has this structure, is alight-emitting device where reliability for a long period of time can beimproved.

In addition, there are not so many wirings dragged from the outside ofor from under a sealing material close to an upper electrode for alight-emitting element in the case of an actual active matrix panel.However, such a structure can be required to be formed, anddeterioration due to the structure occurs naturally. The commercialvalue of a light-emitting device in which a periphery portion is notlighted due to deterioration is dramatically decreased even though theportion is just a part of the light-emitting device. Therefore, thestructure according to the present invention can be preferably used alsoas a measure for a small portion at the periphery of a light-emittingelement.

It is to be noted that it is preferable to provide a desiccant in theinside space surrounded by the sealing material 108. A desiccant can beprovided by being attached to the inside of a concave portion formed inthe opposed substrate 109. Providing a desiccant makes it possible tosuppress deterioration for a longer period of time.

It is to be noted that the structure in the present embodiment mode canbe used in combination with the structures of the other embodimentmodes.

Embodiment Mode 3

FIGS. 2A to 2C show one of structures of a light-emitting deviceaccording to the present invention. For the same components as those inFIG. 1A, the same reference numerals and the same materials can be used.In addition, refer to the description for FIG. 1A since a repeateddescription is omitted. It is to be noted that FIG. 2A is across-sectional view of FIG. 2B along the line A-B and FIG. 2C is across-sectional view of FIG. 2B along the line C-D.

FIG. 2A is different from FIG. 1A in the structure that a wiring 103 hasa width c that is less than 1 mm, preferably 100 μm or less, in thenarrower-side direction of the wiring 103. By this structure, peripherydeterioration can be suppressed even when the wiring 103 is continuouslyformed from outside the sealing material 108 under an upper electrode107 for a light-emitting element.

In addition, in the present embodiment mode, the sealing material 108may be overlapped with the upper electrode 107 for the light-emittingelement as long as the overlap is 15 μm or less. Further, of course,there may be a gap between the sealing material 108 and the upperelectrode 107.

It is to be noted that the structure in the present embodiment can beused in combination with the description in Embodiment Mode 1 or 2.

In addition, there are not so many wirings dragged from the outside ofor from under a sealing material close to an upper electrode for alight-emitting element in the case of an actual active matrix panel.However, such a structure can be required to be formed, anddeterioration due to the structure occurs naturally. The commercialvalue of a light-emitting device in which a periphery portion is notlighted due to deterioration is dramatically decreased even though thedeteriorated portion is just a part of the light-emitting device.Therefore, the structure according to the present invention can bepreferably used also as a measure for a small portion at the peripheryof a light-emitting element.

It is to be noted that it is preferable to provide a desiccant in aregion surrounded by the sealing materials. A desiccant can be providedby being attached to the inside of a concave portion formed in theopposed substrate 109. Providing a desiccant makes it possible tosuppress deterioration for a longer period of time.

It is to be noted that the structure in the present embodiment mode canbe used in combination with the structures of the other embodimentmodes.

Embodiment Mode 4

FIGS. 3A to 3C show one of structures of a light-emitting deviceaccording to the present invention. For the same components as those inFIG. 1A, the same reference numerals and the same materials can be used.In addition, refer to the description for FIG. 1A since a repeateddescription is omitted. It is to be noted that FIG. 3A is across-sectional view of FIG. 3B along the line A-B and FIG. 3C is across-sectional view of FIG. 3B along the line C-D.

A wiring 153 in FIG. 3B has a plurality of wirings 103 arranged, whereeach of the wirings 103 is the wiring 103 shown in FIG. 2B. The wiring103 has a width c that is less than 1 mm, preferably 100 μm or less, inthe narrower-side direction of the wiring 103, and the distance dbetween the wirings 103 is 1 μm or more, preferably 5 μm. When thewiring 153 has a portion where the width c is less than 1 mm, preferably100 μm or less, and the distance d between the wirings 103 is 1 μm ormore, preferably 5 μm, periphery deterioration can be suppressed evenwhen the wiring 153 is continuously formed from outside the sealingmaterial 108 under an upper electrode 107 for a light-emitting element.

In addition, in the present embodiment mode, the sealing material 108may be overlapped with the upper electrode 107 for the light-emittingelement as long as the overlap is 15 μm or less. Further, of course,there may be a gap between the sealing material 108 and the upperelectrode 107.

In addition, there are not so many wirings dragged from the outside ofor from under a sealing material close to an upper electrode for alight-emitting element in the case of an actual active matrix panel.However, such a structure can be required to be formed, anddeterioration due to the structure occurs naturally. The commercialvalue of a light-emitting device in which a periphery portion is notlighted due to deterioration is dramatically decreased even though theportion is just a part of the light-emitting device. Therefore, thestructure according to the present invention can be preferably used alsoas a measure for a small portion at the periphery of a light-emittingelement.

It is to be noted that it is preferable to provide a desiccant in aregion surrounded by the sealing materials. A desiccant can be providedby being attached to the inside of a concave portion formed in theopposed substrate 109. Providing a desiccant makes it possible tosuppress deterioration for a longer period of time.

It is to be noted that the structure in the present embodiment mode canbe used in combination with the structures of the other embodimentmodes.

Embodiment Mode 5

FIGS. 4A to 4C show one of structures of a light-emitting deviceaccording to the present invention. For the same components as those inFIG. 1A, the same reference numerals and the same materials can be used.In addition, refer to the description for FIG. 4A since a repeateddescription is omitted. It is to be noted that FIG. 4A is across-sectional view of FIG. 4B along the line A-B and FIG. 4C is across-sectional view of FIG. 4B along the line C-D.

Between the substrate edge and an upper electrode 107 for alight-emitting element, a wiring 163 in FIG. 4B has a plurality ofopenings that are 1 μm or more, preferably 5 μm or more, in width in thenarrower-side direction of the opening between the substrate edge and anupper electrode 107 for a light-emitting element. The plurality ofopenings are arranged adjacent to each other in the narrower-sidedirection of the opening, and the length between the adjacent openingsis less than 1 mm. This makes it possible to suppress peripherydeterioration without accelerating penetration of water even when thewiring 163 is continuously formed from outside a sealing material 108under the upper electrode 107 for the light-emitting element.

In addition, in the present embodiment mode, the sealing material 108may be overlapped with the upper electrode 107 for the light-emittingelement as long as the overlap is 15 μm or less. Further, of course,there may be a gap between the sealing material 108 and the upperelectrode 107.

In addition, there are not so many wirings dragged from the outside ofor from under a sealing material close to an upper electrode for alight-emitting element in the case of an actual active matrix panel.However, such a structure can be required to be formed, anddeterioration due to the structure occurs naturally. The commercialvalue of a light-emitting device in which a periphery portion is notlighted due to deterioration is dramatically decreased even though thedeteriorated portion is just a part of the light-emitting device.Therefore, the structure according to the present invention can bepreferably used also as a measure for a small portion at the peripheryof a light-emitting element.

It is to be noted that it is preferable to provide a desiccant in aregion surrounded by the sealing materials. A desiccant can be providedby being attached to the inside of a concave portion formed in theopposed substrate 109. Providing a desiccant makes it possible tosuppress deterioration for a longer period of time.

It is to be noted that the structure in the present embodiment mode canbe used in combination with the structures of the other embodimentmodes.

Embodiment Mode 6

FIGS. 5A to 5C shows some structures of a light-emitting deviceaccording to the present invention. For the same components as those inFIG. 1A, the same reference numerals and the same materials can be used.

FIG. 5A shows a structure that is similar to the structure shown in FIG.1B, where passivation films 110 a and 110 b are respectively formedunder wirings 103 a and 103 b. The passivation films 110 a and 110 b areformed by using an insulating film including silicon as its maincomponent, and composed of an inorganic film. It can be said that theinorganic film has a two-layer structure of the passivation film and thewiring. Alternatively, the inorganic film can be a wiring that has atwo-layer structure when the passivation films 110 a and 110 b areformed by using a conductive material.

FIG. 5B shows a structure that is similar to the structure shown in FIG.1B, where a passivation film 111 is formed in contact with an upperelectrode 107 for a light-emitting element. The passivation film 111 canbe formed by an insulating film including silicon as its main component,and in that case, which is an inorganic film. Therefore, when the gapbetween wirings 103 a and 103 b is formed in a region between a sealingmaterial 108 and the passivation film 111, a structure according to thepresent invention can be satisfied so that periphery deterioration canbe suppressed.

It is to be noted that the passivation film 111 can be considered to becomposed of an organic material, and in that case, may be treated as thesame structure as that in FIG. 1B.

FIG. 5C shows a light-emitting device that has both the structures shownin FIGS. 5A and 5B. This structure may be employed.

It is to be noted the present embodiment mode can be applied to otherstructures although the structure shown in FIG. 1B is given as anexample for the descriptions in the present embodiment mode. Inaddition, the structures in the embodiment mode can be used incombination with the structures in the other embodiment modes.

Embodiment Mode 7

FIGS. 6A to 6C and FIGS. 7A and 7B show some structures of alight-emitting device according to the present invention. For the samecomponents as those in FIG. 1A, the same reference numerals and the samematerials can be used.

FIG. 6A shows an example in which a lower electrode 112 for alight-emitting element and wirings 103 a and 103 b are formed ondifferent insulating films. The lower electrode 112 for thelight-emitting element is electrically connected to a wiring 103 cthrough a contact hole provided in a second organic insulating film 105.The lower electrode 112 has an edge portion covered with a third organicinsulating film 113, and on the third organic insulating film 113, alight-emitting laminated body 106 is continuously formed to cover anexposed portion of the lower electrode 112. Further, an upper electrode107 for the light-emitting element is provided to cover thelight-emitting laminated body 106. A substrate 100 with a baseinsulating film 101, a first organic insulating film 102, the wirings103 a, 103 b, and 103 c, the lower electrode 112 for the light-emittingelement, the second organic insulating film 105, the light-emittinglaminated body 106, and the upper electrode 107 for the light-emittingelement is attached to an opposed substrate 109 with a sealing material108.

The third organic insulating film 113 is formed to cover the lowerelectrode 112, and is also formed on the second organic insulating film105. Therefore, a laminated structure of the second organic insulatingfilm 105 and the third organic insulating film 113 is formed. An edgeportion of the third organic insulating film 113 is formed so as not tobe overlapped with an edge portion of the second organic insulating film105, that is, closer to the light emitting than the edge portion of thesecond organic insulating film 105. It is preferable that the edgeportion of the third organic insulating film 113 be formed closer to thelight emitting than a portion of the second organic insulating film 105from which the film thickness thereof is decreased toward the edgeportion thereof.

As described above, also in the example where the lower electrode 112for the light-emitting element and the wirings 103 a and 103 b areformed on different insulating films, providing a gap between thewirings 103 a and 103 b and a gap between the sealing material 108 andthe upper electrode 107 for the light-emitting element makes it possibleto suppress penetration of water in a portion where the two gaps areoverlapped with each other, and in addition, which leads to suppressionof periphery deterioration.

FIG. 6B shows a structure in which the structure shown in FIG. 6A andthe structure shown in FIG. 5A are combined. Also in this structure,providing a gap between a lamination of a wiring 103 a and a passivationfilm 110 a and a lamination of a wiring 103 b and a passivation film 110b and a gap between a sealing material 108 and a upper electrode 107 fora light-emitting element makes it possible to suppress penetration ofwater in a portion where the two gaps are overlapped with each other,and in addition, which leads to suppression of periphery deterioration.

FIG. 6C shows an example in which a passivation films 114 a, 114 b, and114 c below a lower electrode 112 for a light-emitting element is addedto the structure shown in FIG. 6A. The passivation films 114 a, 114 b,and 114 c is formed by using an insulating film including silicon as itsmain component, and composed of an inorganic film. In this case, it isnecessary that a gap be provided between the passivation films 114 a and114 b to be overlapped with at least a portion of the gap wirings 103 aand 103 b.

As described above, also in the example where the passivation films 114a, 114 b, and 114 c below the lower electrode 112 for the light-emittingelement are formed, providing a gap between the wirings 103 a and 103 band a gap between the passivation films 114 a and 114 b and overlappingthe gaps partly make it possible to suppress penetration of water in aportion where the two gaps and a gap between a sealing material 108 andan upper electrode 107 for the light-emitting element are overlappedwith each other, and in addition, which leads to suppression ofperiphery deterioration.

FIG. 7A shows a structure in which the structure shown in FIG. 6A iscombined with the structure shown in FIG. 5B to provide a passivationfilm 115 on an upper electrode 107 for a light-emitting element. Also inthis structure, providing a gap between wirings 103 a and 103 b and agap between a sealing material 108 and the passivation film 115 makes itpossible to suppress penetration of water in a portion where the twogaps are overlapped with each other, and in addition, which leads tosuppression of periphery deterioration.

FIG. 7B shows a structure in which the structures shown in FIGS. 6A to6C and FIG. 7A are combined. Also in this structure, providing a gapbetween the wirings 103 a and 103 b and a gap between the passivationfilms 114 a and 114 b and overlapping the gaps partly make it possibleto suppress penetration of water in a portion where the two gaps and agap between a sealing material 108 and a passivation film 115 areoverlapped with each other, and in addition, which leads to suppressionof periphery deterioration.

It is to be noted that the lower electrode 112 for the light-emittingelement can be formed by using the same material for the lower electrodeshown in FIG. 1A and that the third organic insulating film 113 can beformed by using the same material for the first organic insulating film102 or the second organic insulating film 105.

It is to be noted that the structures in the present embodiment mode canbe used in combination with the structures of the other embodimentmodes.

Embodiment Mode 8

Subsequently, a method for manufacturing a light-emitting deviceaccording to the present invention will be described with references toFIGS. 8A to 8D and FIGS. 9A to 9C.

First, after forming a first base insulating layer 201 and a second baseinsulating layer 202 over a substrate 200.

Glass, quartz, plastic (such as polyimide, acrylic, polyethyleneterephthalate, polycarbonate, polyacrylate, or polyethersulfone), or thelike can be used as a material for the substrate 200. The substrate maybe used after being polished by CMP or the like, if necessary. In thepresent embodiment mode, a glass substrate is used.

The first base insulating layer 201 and the second base insulating layer202 are provided in order to prevent an element that has a damagingeffect on characteristics of a semiconductor film, such as an alkalimetal or an alkaline earth metal contained in the substrate 200, fromdiffusing into the semiconductor layer 203. Silicon oxide, siliconnitride, silicon oxide containing nitrogen, silicon nitride containingoxygen, or the like can be used as a material thereof. In the presentembodiment, the first base insulating layer 201 and the second baseinsulating layer 202 are formed by using silicon nitride, silicon oxiderespectively. Although a base insulating layer is formed by two layersof the first base insulating layer 201 and the second insulating layer202 in the present embodiment, the base insulting layer may be formed bya single layer, or by a multilayer of two or more layers. Alternatively,it is not necessary to provide the base insulating film when diffusionsof impurities from the substrate are negligible.

An amorphous silicon film is formed to be 25 to 100 nm (preferably, 30to 60 nm) in thickness on the second base insulating layer 202. A knownmethod such as sputtering, low pressure CVD, or plasma CVD can be usedas a manufacturing method thereof. Subsequently, a heat treatment at500° C. for one hour is performed for dehydrogenation.

Then, the amorphous silicon film is crystallized with the use of a laserirradiation system to form a crystalline silicon film. As to the lasercrystallization in the present embodiment mode, an excimer laser isused, and an emitted laser beam is processed with an optical system tobe a linear beam spot. The amorphous silicon film is irradiated with thelinear beam spot to be a crystalline silicon film, which is used as thesemiconductor film.

As another method for crystallizing an amorphous silicon film, there isa method of performing crystallization only by heat treatment, a methodof performing crystallization by heat treatment with the use of a metalelement that promotes crystallization, or the like. Nickel, iron,palladium, tin, lead, cobalt, platinum, copper, gold, and the like canbe used as the element that promotes crystallization. By using theelement, crystallization can be performed at a lower temperature in ashorter time, compared to the case of performing crystallization only byheat treatment. Therefore, a glass substrate or the like is lessdamaged. In the case of performing crystallization only by heattreatment, a highly heat-resistant quartz substrate or the like may beused as the substrate 200.

Subsequently, addition of a small amount of impurity, so-called channeldoping, is performed to the semiconductor film to control a thresholdvoltage, if necessary. An n-type or p-type impurity (phosphorus, boron,or the like) is added by an ion doping method to obtain a requiredthreshold voltage.

Thereafter, patterning of the semiconductor film is performed into apredetermined shape as shown in FIG. 8A to obtain the island-shapedsemiconductor layer 203. The patterning is performed in such a way thata photoresist is applied to the semiconductor film, exposed to light tohave a predetermined mask shape, and baked to form a resist mask on thesemiconductor film, and etching is performed by using the mask.

Subsequently, a gate insulating film 204 is formed to cover thesemiconductor layer 203. Then, a first conductive layer 205 and a secondconductive layer 206 are formed on the gate insulating film 204 (FIG.8A). The gate insulating film 204 is an insulating layer containingsilicon and formed by plasma CVD or sputtering to be 40 to 150 nm inthickness. In the present embodiment, the gate insulating layer 204 isformed by using silicon oxide.

The first conductive film 205 and the second conductive film 206 may beformed by using an element selected from tantalum, tungsten, titanium,molybdenum, aluminum, copper, chromium, and niobium, or by using analloy material or compound material mainly containing the element. Asemiconductor film typified by a polycrystalline silicon film doped withan impurity element such as phosphorus may be used. Alternatively, anAgPdCu alloy may be used.

Next, the first conductive film 205 and the second conductive film 206on the gate insulating film 204 are etched to form a gate electrode thathas a first conductive layer 207 and a second conductive layer 208 andan external connecting portion that has a first conductive layer 209 anda second conductive layer 210, where the gate electrode is overlappedwith the semiconductor layer 203 with the gate insulating filminterposed therebetween (FIG. 8B). In the present embodiment mode,tantalum nitride (TaN) with a film thickness of 30 nm as the firstconductive film 205 is formed on the gate insulating film 204, andtungsten (W) with a film thickness of 370 nm as the second conductivefilm 206 is formed thereon. It is to be noted that, although the firstconductive film 205 is TaN with the film thickness of 30 nm and thesecond conductive film 206 is W with the film thickness of 370 nm in thepresent embodiment mode, the first conductive film 205 and the secondconductive film 206 may be formed to have thicknesses in the ranges of20 to 100 nm and 100 to 400 nm respectively. Further, although alaminated structure of the two layers is employed in the presentembodiment, a single layer structure may be employed, or a laminatedstructure of three or more layers may be employed.

Then, in order to form the gate electrode, the external connectingportion, and a wiring that is not illustrated by etching the firstconductive film 205 and the second conductive film 206, a mask, forexample, a resist mask is formed through exposure to light byphotolithography. In a first etching process, etching is carried outtwice under first and second etching conditions. Although the etchingconditions may be selected appropriately, etching is carried out by thefollowing method in the present embodiment.

In the first etching process, ICP (Inductively Coupled Plasma) etchingis used. As for the first etching condition, while using CF₂, Cl₂ and O₂as an etching gas at the gas flow ratio of 17/17/10, an RF power (13.56MHz) of 500 W is applied to a coiled electrode under a pressure of 1.5Pa to generate plasma for etching. An RF power (13.56 MHz) of 120 W isapplied also to a substrate side (sample stage) to apply a substantiallynegative self-bias voltage. The W film is etched under the first etchingcondition to make an edge portion of the first conductive film into atapered shape.

Subsequently, etching is carried out under the second etching condition.Etching is performed for about 17 seconds with the mask left in such away that an RF power (13.56 MHz) of 500 W is applied to the coilelectrode under a pressure of 1.5 Pa to generate plasma for etchingwhile using CF₄ and Cl₂ as an etching gas at the gas flow ratio of20/20. An RF power (13.56 MHz) of 10 W is applied also to a substrateside (sample stage) to apply a substantially negative self-bias voltage.Under the second etching condition in which CF₄ and Cl₂ are mixed, boththe W film and the TaN film are etched to the same extent. In the firstetching process, edge portions of the first and second conductive filmare made tapered due to the bias voltages applied to the substrate side.

Next, a second etching process is carried out without removing the mask.In the second etching process, etching is performed for about 25 secondsin such a way that, while using SF₆, Cl₂, and O₂ as an etching gas atthe gas flow ratio of 16/8/30, an RF power (13.56 MHz) of 700 W isapplied to the coil electrode under a pressure of 2.0 Pa to generateplasma. An RF power (13.56 MHz) of 0 W is applied also to a substrateside (sample stage) to apply a substantially negative self-bias voltage.The W film is selectively etched under this etching condition to form aconductive layer in a second shape. The first conductive film is hardlyetched at this time. The gate electrode of the first conductive layer207 and the second conductive layer 208, and the external connectingportion of the first conductive layer 209 and the second conductivelayer 210 are formed by the first and second etching processes.

Then, a first doping process is carried out without removing the mask.Thus, the semiconductor layer 203 is doped with an n-type impurity at alow concentration. The first doping process may be performed by iondoping or ion implantation. The ion doping may be performed underconditions where the dose amount is from 1×10¹³ to 5×10¹⁴ atoms/cm² andthe acceleration voltage is from 40 to 80 kV. In the present embodimentmode, the ion doping is carried out at an acceleration voltage of 50 kV.An element belonging to Group 15 of the periodic table may be used asthe n-type impurity, and typically, phosphorus (P) or arsenic (As) isused. In the present embodiment mode, phosphorus (P) is used. In thiscase, a first impurity region (N⁻⁻ region) that is doped with alow-concentration impurity in a self-alignment manner is formed with thefirst conductive layer 207 as a mask.

Subsequently, the mask is removed. Then, a mask, for example, a resistmask is newly formed, and a second doping process is carried out at ahigher acceleration voltage than that in the first doping process. Alsoin the second doping process, the semiconductor layer 203 is doped withan n-type impurity as well. The ion doping may be performed underconditions where the dose amount is from 1×10¹³ to 3×10¹⁵ atoms/cm² andthe acceleration voltage is from 60 to 120 kV. In the present embodimentmode, the ion doping is carried out with the dose amount of 3.0×10¹⁵atoms/cm² and the acceleration voltage of 65 kV. In the second dopingprocess, doping is carried out so that the semiconductor layer locatedunder the first conductive layer 207 is also doped with the impurityelement with the use of the second conductive layer 208 of the gateelectrode as a mask against the impurity element. It is to be noted thatthe semiconductor layer 203 illustrated in FIG. 8B in the presentembodiment mode is covered with the mask to operate as a p-type thinfilm transistor.

It is to be noted that although the respective impurity regions areformed by performing the two doping processes in the present embodimentmode, the present invention is not limited to this. An impurity regionthat has a desired impurity concentration may be formed by performingdoping once or more times under appropriate conditions.

Next, after removing the mask, a mask, for example, a resist mask isnewly formed to perform a third doping process. By the third dopingprocess, a P⁺ region 212 and P⁻ region 211 are formed in thesemiconductor layer 203 to serve as a p-channel TFT, which are dopedwith a p-type impurity element.

As the p-type impurity element, elements belonging to the group 13 ofthe periodic table, such as boron (B), aluminum (Al), and gallium (Ga),are known.

In the present embodiment mode, boron (B) is selected as the p-typeimpurity element, and the P⁺ region 212 and the P⁻ region 211 are formedby ion doping using diborane (B₂H₆). The ion doping is carried out underconditions where the dose amount is 1×10¹⁶ atoms/cm² and theacceleration voltage is 80 kV.

It is to be noted that the semiconductor layer 203 forming N-channel TFTis covered with the mask in the third doping process.

It is to be noted that although the P⁺ region 212 and the P⁻ region 211are formed by performing the third doping process once in the presentembodiment mode, the present invention is not limited to this. P⁺ regionand a P⁻ region may be formed by plural doping processes appropriatelyaccording to each condition.

In this way, a thin film transistor including the semiconductor layer,the gate insulating film, and the gate electrode is formed. It is to benoted that a method for manufacturing a thin film transistor is notlimited to this, a thin film transistor may be manufacturedappropriately by a known manufacturing method. Further, it is possiblefor users to determine the polarity of a TFT freely.

In the present embodiment, a top-gate thin film transistor using acrystalline silicon film crystallized by using laser crystallization ismanufactured. However, a bottom-gate thin film transistor using anamorphous semiconductor film can be used for a pixel portion. Silicongermanium as well as silicon can be used for the amorphoussemiconductor. In the case of using silicon germanium, it is preferablethat the concentration of germanium be approximately 0.01 to 4.5 atomic%. A microcrystalline semiconductor (semi-amorphous semiconductor) film,in which a crystal grain of 0.5 to 20 nm can be observed within anamorphous semiconductor, may be used. A microcrystal in which a crystalgrain of 0.5 to 20 nm can be observed is also referred to as amicrocrystal (μc).

Semi-amorphous silicon (also referred to as SAS) that is asemi-amorphous semiconductor can be obtained by glow dischargedecomposition of a silicide gas. SiH₄ is used as a typical silicide gas.In addition, Si₂H₆, SiH₂Cl₂, SiHCl₃, SiCl₄, SiF₄, and the like can alsobe used as the silicide gas. SAS can be formed easily by diluting thesilicide gas with hydrogen or with hydrogen and one or more rare gaselements selected from helium, argon, krypton, and neon. It ispreferable to dilute the silicide gas so that the dilution ratio rangesfrom 10 to 1000 times. Reaction production of a film by glow dischargedecomposition may be performed under a pressure in the range of 0.1 to133 Pa. A high-frequency power of 1 to 120 MHz, preferably, 13 to 60 MHzmay be supplied to generate glow discharge. It is preferable that thesubstrate heating temperature be preferably 300° C. or less, and asubstrate heating temperature in the range of 100 to 250° C. ispreferred.

The thus formed SAS has a Raman spectrum shifted to a lower frequencyside than 520 cm⁻¹. In X-ray diffraction, diffraction peaks of (111) and(220) that are considered due to a crystal lattice of silicon areobserved. The SAS contains hydrogen or halogen of at least 1 atomic % ormore to terminate a dangling bond. It is desirable that anatmospheric-component impurity such as oxygen, nitrogen, or carbon is1×10²⁰/cm³ or less as an impurity element in the film, and particularly,the oxygen concentration is 5×10¹⁹/cm³ or less, preferably 1×10¹⁹/cm³ orless. When the SAS is used for a TFT, the mobility thereof is μ=1cm²/Vsec to 10 cm²/Vsec.

In addition, this SAS may be further crystallized with a laser.

Subsequently, an insulating film (hydrogenation film) 213 is formed byusing silicon nitride to cover the gate electrode of the firstconductive layer 207 and the second conductive layer 208, the externalconnecting portion of the first conductive layer 209 and the secondconductive layer 210, and the gate insulating film 204, and a heattreatment is performed at 480° C. for about an hour to activate theimpurity elements and hydrogenate the semiconductor layer 203. Then, aninterlayer insulating layer 214 is formed to cover the insulating film(hydrogenation film) 213 (FIG. 8C). As a material for forming theinterlayer insulating layer 214, a self-flatness material such asacrylic, polyimide, or siloxane may be used. In the present embodimentmode, siloxane is formed as a first interlayer insulating layer.

Next, contact holes reaching the semiconductor layer 203 and theexternal connecting portion are formed. The contact holes can be formedby etching with the use of a mask, for example, a resist mask, untilexposing the semiconductor layer 203 and the external connectingportion, and can be formed by either wet etching or dry etching. It isto be noted that etching may be performed once or divided into more thanonce according to the condition. When etching is performed more thanonce, both wet etching and dry etching may be used.

Then, a conductive layer is formed to cover the contact holes and theinterlayer insulating layer. The conductive layer is processed into apredetermined shape with the use of a mask, for example, a resist mask,to form electrodes 215 and 216 to serve as a source electrode or a drainelectrode and wirings 217 and 218 (FIG. 8D). These electrodes andwirings may be a single layer of aluminum, copper or the like. However,in the present embodiment mode, these electrodes and wirings have alaminated structure of molybdenum, aluminum, and molybdenum formed inthis order. As a laminated wiring, a structure of titanium, aluminum,and titanium, and a structure of titanium, titanium nitride, aluminum,and titanium may be employed.

There is a gap between an inner edge of the wiring 217 and an outer edgeof the wiring 218, the wiring 218 is formed closer to the light emittingelement than the wiring 217, over the interlayer insulating layer 214.Further, it is desirable that the gap is 5 μm or more, preferably 10 μmor more, and more preferably 20 μm or more.

After forming a light-transmitting conductive layer that is partiallyoverlapped with an exposed portion of the drain electrode 216, thelight-transmitting conductive layer is processed with the use of a mask,for example, a resist mask, to form a lower electrode 220 for a thinfilm light-emitting element and an external connecting portion 221,where the lower electrode 220 is electrically connected to the drainelectrode 216.

Further, in the present embodiment mode, the lower electrode 220 isformed as an anode, for which it is preferable to use a metal, an alloy,an electrically conductive compound, a mixture of these materials, orthe like that has a larger work function (a work function of 4.0 eV ormore). For example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W),chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu),palladium (Pd), a nitride (TiN) of a metal material, and the like can beused in addition to ITO (indium tin oxide), ITO including silicon(ITSO), IZO (indium zinc oxide) of indium oxide mixed with 2 to 20% zincoxide (ZnO), zinc oxide, and GZO (Gallium Zinc Oxide) of zinc oxidemixed with gallium. In the present embodiment, an ITSO is used for thelower electrode 220.

An insulating film including an organic material is formed to cover theinterlayer insulating layer 214, the lower electrode 220, and wirings217, 218. Subsequently, the insulating layer is processed so that aportion of the lower electrode 220 and the external connecting portionare exposed, and a partition 222 is thus formed (FIG. 9A). As a materialfor the partition 222, a photosensitive organic material (acrylic,polyimide, siloxane or the like) is preferably used. However, anon-photosensitive organic material may be used. Further, as a materialof the partition 222, a black pigment or dye such as black titanium orcarbon nitride may be dispersed with the use of a dispersant to make thepartition 222 black like a black matrix. It is preferable that an edgeside of the partition 222 toward the lower electrode 220 have acurvature and a tapered shape in which the curvature is continuouslychanging.

Next, a light-emitting laminated body 223 is formed to cover the lowerelectrode 220 exposed continuously from the partition 222. Thelight-emitting laminated body 223 may be formed by evaporation, spincoating, the ink-jet method or the like. Subsequently, an upperelectrode 224 is formed to cover the light-emitting laminated body 223(FIG. 9B). Therefore, a light-emitting element including the lowerelectrode 220, the light-emitting laminated body 223, and the upperelectrode 224 can be manufactured. The upper electrode 224 is formed asa cathode in the present embodiment mode, and as a cathode material, itis preferable to use a metal, an alloy, an electrically conductivecompound, a mixture of these materials, or the like that has a smallerwork function (a work function of 3.8 eV or less). Specific examples ofthe cathode material include an element belonging to Group 1 or 2 of theperiodic table, that is, alkali metals such as Li and Cs, alkali-earthmetals such as Mg, Ca, and Sr, alloys (Mg:Ag and Al:Li), compounds (LiF,CsF, and CaF₂) each containing the element, and transition metalsincluding rare-earth metals, which can be used for forming the cathode.However, the cathode can be formed by lamination of a metal (alloy isincluded) such as Al, Ag, or ITO. In the present embodiment mode,aluminum is used for the cathode.

It is to be noted that although the electrode electrically connected tothe drain electrode 216 is the anode in the present embodiment mode, thecathode may be electrically connected to the drain electrode 216.

After that, a silicon oxide film containing nitrogen may be formed byplasma CVD as a passivation film by plasma CVD. In the case of using asilicon oxide film containing nitrogen, a silicon oxynitride film thatis manufactured by using SiH₄, N₂O, and NH₃, a silicon oxynitride filmthat is manufactured by using SiH₄ and N₂O, or a silicon oxynitride filmthat is manufactured gas of SiH₄ and N₂O diluted with Ar may be formedby plasma CVD.

Alternatively, a silicon oxynitride hydride film that is manufactured byusing SiH₄, N₂O, and H₂ may be used as the passivation film. Naturally,the structure of the passivation film is not limited to a single layerstructure. The passivation film may have a single layer structure orlaminated structure using another insulating layer including silicon. Inaddition, a multilayer film of a carbon nitride film and a siliconnitride film, a multilayer film of a styrene polymer, a silicon nitridefilm, or a diamond like carbon film may be formed instead of the siliconoxide film containing nitrogen.

Forming the passivation film makes it possible to suppress penetrationof elements that accelerate deterioration of the light-emitting elementfrom the surface of the light-emitting element, which leads toimprovement in reliability.

Subsequently, sealing of a display portion is performed to protect thelight-emitting element from materials, such as water, that acceleratedeterioration (FIG. 9C). In the case of using an opposed substrate 226for sealing, a sealing material 225 comprising insulating material isused to attach the opposed substrate 226. There is a gap between an edgeof the sealing material 225 and an edge of the upper electrode 224. Thesealing material 225 is formed closer to an edge of the substrate 200than an edge of the upper electrode 224.

At least a portion of the gap between the sealing material 225 and theupper electrode 224 is required to be formed to overlap with the gapbetween the wiring 217 and the wiring 218.

As shown in FIG. 9A, when the wiring 217 is formed from the outside ofthe sealing material 225 toward the inside of the sealing material 225,or from under the sealing material 225 toward the inside of the sealingmaterial 225, penetration of water is accelerated. Therefore, it isbetween the wiring 217 and the wiring 218 formed under the upperelectrode 107 that the gap is necessary.

The space between the opposed substrate 226 and the element substratemay be filled with a inert gas such as dried nitrogen. It is preferableto use an ultraviolet curable resin or the like for the sealing material225. The sealing material 225 may be mixed with a drying agent orparticles for keeping a gap between the substrates constant.

After that, a light-emitting device according to the present inventionis completed by attaching a flexible printed circuit (FPC) 228 to theexternal connecting portion 221 with an anisotropic conductive film 227interposed therebetween.

In the present embodiment mode, the structure in Embodiment Mode 2 isapplied. However, also when the structures in the other embodiment modesare applied, a light-emitting device where periphery deterioration canbe suppressed can be manufactured.

In the thus manufactured light-emitting device, further penetration ofwater penetrating the light-emitting device through an organic film fromthe outside atmosphere of the light emitting device can be suppressed ata portion where the gaps explained above are formed. In addition, thismakes it possible to suppress periphery deterioration of thelight-emitting device.

Embodiment Mode 9

The appearance of a panel in a light-emitting device manufactured inaccordance with Embodiment Mode 8 will be described with reference toFIG. 10. It is to be noted that same reference numerals are used for thesame portions as those in Embodiment Mode 8. FIG. 10 is a top view of apanel in which a transistor and a light-emitting element that are formedover the substrate 200 are sealed with a sealing material formed betweena substrate 200 and an opposed substrate 226, and FIG. 9C corresponds toa cross-sectional view of FIG. 10 along E-F. Further, thecross-sectional views in FIGS. 1A, 1B, 2A, 3A, and 4A and FIGS. 5A to 7Ccorrespond G-H or I-J in FIG. 10. As a matter of course, the structureaccording to the present invention can be applied to any portions at theperiphery of the panel, and also can be applied to only a portion of apanel.

An upper electrode 224 for the light-emitting element is formed to covera pixel portion in which the light-emitting element provided over thesubstrate 200 is formed, and a sealing material 225 is provided tosurround a signal line driver circuit 4003 and a scan line drivercircuit 4004. The opposed substrate 226 is provided over the pixelportion, the signal line driver circuit 4003, and the scan line drivercircuit 4004. Thus, the pixel portion, the signal line driver circuit4003, and the scan line driver circuit 4004 are sealed with thesubstrate 200, the sealing material 225, and the opposed substrate 226.An the sealing material 225 is formed closer to the edge of thesubstrate 200 than the edge of the upper electrode 224 for thelight-emitting element, or formed so as to be overlapped with the edgeof the upper electrode 224. The overlap is 15 μm or less. It is to benoted that, in the case of having the structure in Embodiment Mode 1 or2, the upper electrode 224 and the sealing material 225 are not allowedto have contact with each other.

Further, the pixel portion, the signal line driver circuit 4003, and thescan line driver circuit 4004, which are provided over the substrate200, have a plurality of thin film transistors. FIG. 9C shows a thinfilm transistor that is included in the pixel portion.

In addition, the light-emitting element is electrically connected to thethin film transistor.

A flexible printed circuit (FPC) 228 supplies a signal or a power supplyvoltage to the pixel portion, the signal line driver circuit 4003, andthe scan line driver circuit 4004 through an external connecting portion221 and a wiring 217.

It is to be noted that either an analog video signal or a digital videosignal may be used in this light-emitting device that has a displayfunction. In the case of using a digital video signal, the video signalis classified into a video signal using voltage or a video signal usingcurrent. When a light-emitting element emits light, a video signal thatis input into a pixel is classified into a constant-voltage signal or aconstant-current signal. When the video signal is a constant-voltagesignal, the voltage applied to the light-emitting element or the currentflowing in the light-emitting element is constant. On the other hand,when the video signal is a constant-current signal, the voltage appliedto the light-emitting element or the current flowing in thelight-emitting element is constant. The case in which the voltageapplied to the light-emitting element is constant is referred to as aconstant voltage driving while the case in which the current flowing inthe light-emitting element is constant is referred to as constantcurrent driving. In the constant current driving, a constant currentflows regardless of change in the resistance of the light-emittingelement. For the light-emitting device and driving method thereof,either a video signal using voltage or a video signal using current maybe used, and either constant voltage driving or constant current drivingmay be employed.

It is to be noted that the light-emitting device according to thepresent invention includes, in its category, a panel in which a pixelportion including a light-emitting element is formed and a module inwhich an IC is mounted on the panel.

In a panel and a module as described in the present embodiment mode,further penetration of water penetrating through an organic film fromthe outside atmosphere of the light emitting device can be suppressed byproviding a gap between the wirings 217 and 218 and a gap between thesealing member 225 and the upper electrode 224. In addition, this makesit possible to suppress periphery deterioration of a light-emittingdevice.

Embodiment Mode 10

Electronic devices mounted with a module according to the presentinvention, as shown in FIGS. 11A to 11E as examples, include a videocamera, a digital camera, a goggle-type display (head mount display), anavigation system, a sound reproduction device (a car audio component orthe like), a laptop personal computer, a game machine, a personaldigital assistance (a mobile computer, a cellular phone, a portable gamemachine, an electronic book, or the like), and an image reproductiondevice equipped with a recording medium (specifically, a device equippedwith a display, which can reproduce a recording medium such as a DigitalVersatile Disc (DVD) and display the image). Specific examples of theseelectronic devices are shown in FIGS. 11A to 11E.

FIG. 11A is a light-emitting device, to which a television set or thelike corresponds. A frame body 2001, a display portion 2003, a speakerportion 2004, and the like are included. In the light-emitting displaydevice, deterioration of a light-emitting element in the display portion2003 is suppressed, and the reliability is improved. A pixel portion maybe provided with a polarizing plate or a circularly polarizing plate inorder to enhance the contrast. For example, films of a ¼λ, plate, a ½λ,plate, and a polarizing plate may be sequentially formed over a sealingsubstrate. Further, an anti-reflective film may be provided over thepolarizing plate.

FIG. 11B is a cellular phone, which includes a main body 2101, a framebody 2102, a display portion 2103, a voice input portion 2104, a voiceoutput portion 2105, an operation key 2106, an antenna 2108, and thelike. In the cellular phone according to the present invention,deterioration of a light-emitting element in the display portion 2103 issuppressed, and the reliability is improved.

FIG. 11C is a laptop computer, which includes a main body 2201, a framebody 2202, a display portion 2203, a keyboard 2204, an externalconnection port 2205, a pointing mouse 2206, and the like. In the laptoppersonal computer according to the present invention, deterioration of alight-emitting element in the display portion 2203 is suppressed, andthe reliability is improved.

FIG. 11D is a mobile computer, which includes a main body 2301, adisplay portion 2302, a switch 2303, an operation key 2304, an infraredport 2305, and the like. In the mobile computer according to the presentinvention, deterioration of a light-emitting element in the displayportion 2302 is suppressed, and the reliability is improved.

FIG. 11E is a portable game machine, which includes a frame body 2401, adisplay portion 2402, a speaker portion 2403, operation keys 2404, arecording medium insert portion 2405, and the like. In the portable gamemachine according to the present invention, deterioration of alight-emitting element in the display portion 2402 is suppressed, andthe reliability is improved.

As described above, the present invention is capable of quite wideapplication, and can be thus used for electronic devices in all fields.

Embodiment Mode 11

In this present embodiment mode, the structure of the light-emittinglaminated body will be described in detail.

The light-emitting laminated body is formed by using a chargeinjecting/transporting material including an organic compound orinorganic compound and a luminescent material. The light-emittinglaminated body includes one or more of layers each including a lowmolecular weight organic compound, an intermediate molecular weightorganic compound (referring to an organic compound which has nosublimation property and has 20 molecules or less or a chained moleculeof 10 μm or less in length), or a high molecular weight organiccompound, and may be combined with an electron injecting/transporting orhole injecting/transporting inorganic compound.

Highly electron transporting materials among chargeinjecting/transporting materials include a metal complex that has aquinoline skeleton or a benzoquinoline skeleton, such astris(8-quinolinolato)aluminum (abbreviation: Alq₃),tris(5-methyl-8-quinolinolato)aluminum (abbreviation: Almq₃),bis(10-hydroxybenzo[h]-quinolinato)beryllium (abbreviation: BeBq₂), andbis(2-methyl-8-quinolinolato)-4-phenylphenolato-aluminum (abbreviation:BAlq). In addition, highly hole transporting materials include anaromatic amine compound (that is, a compound that has a benzenering-nitrogen bond), such as4,4′-bis[N-(1-naphthyl)-N-phenyl-amino]-biphenyl (abbreviation: α-NPD),4,4′-bis[N-(3-methylphenyl)-N-phenyl-amino]-biphenyl (abbreviation:TPD), 4,4′,4″-tris(N,N-diphenyl-amino)-triphenylamine (abbreviation:TDATA), and4,4′,4″-tris[N-(3-methylphenyl)-N-phenyl-amino]-triphenylamine(abbreviation: MTDATA).

Further, highly electron injecting materials among chargeinjecting/transporting materials include a compound of an alkali metalor an alkali-earth metal, such as lithium fluoride (LiF), cesiumfluoride (CsF), and calcium fluoride (CaF₂). In addition, a mixture of ahighly electron transporting material such as Alq₃ and an alkali-earthmetal such as magnesium (Mg) may be used.

Highly hole injecting material among charge injecting/transportingmaterials include metal oxides such as molybdenum oxide (MoOx), vanadiumoxide (VOx), ruthenium oxide (RuOx), tungsten oxide (WOx), and manganeseoxide (MnOx), and further, phthalocyanine compounds such asphthalocyanine (abbreviation: H₂Pc) and copper phthalocyanine (CuPc).

The light-emitting layer included in the light-emitting laminated bodymay have a structure in which a light-emitting layer that shows adifferent emission wavelength band is formed on a pixel to pixel basisfor color display. Typically, a light-emitting layer corresponding toeach color of R (red), G (green), and B (blue) is formed. Also in thiscase, a filter through which light of the emission wavelength band istransmitted is provided on the side to which light is emitted in a pixelso that the color purity can be improved and that the pixel portion canbe prevented from being like a mirror surface (reflecting). When thefilter (coloring layer) is provided, a circular polarization plate to berequired conventionally and the like can be omitted so that loss oflight emitted from the light-emitting layer can be eliminated. Further,variations in color tone can be reduced in the case of viewing the pixelportion (display screen) obliquely.

Luminescent materials include various materials. Among low molecularweight organic luminescent materials,4-dicyanomethylene-2-methyl-6-(1,1,7,7-tetramethyljulolidyl-9-ethenyl)-4H-pyran(abbreviation: DCJT),4-dicyanomethylene-2-t-butyl-6-(1,1,7,7-tetramethyljulolidine-9-enyl]-4H-pyran(abbreviation: DPA), periflanthene,2,5-dicyano-1,4-bis(10-methoxy-1,1,7,7-tetramethyljulolidine-9-enyl)benzene,N,N′-dimethylquinacridon (abbreviation: DMQd), coumarin 6, coumarin545T, tris(8-quinolinolate)aluminum (abbreviation: Alq₃),9,9′-bianthryl, 9,10-diphenylanthracene (abbreviation: DPA),9,10-bis(2-naphthyl)anthracene (abbreviation: DNA), and the like can beused. In addition, another material can also be used.

On the other hand, high molecular weight organic luminescent materialsare physically stronger than low molecular weight materials, and havehigher durability in light-emitting elements. In addition, since highmolecular weight materials can be deposited by coating, light-emittingelements are relatively easily manufactured. The structure of alight-emitting element using a high molecular weight organic luminescentmaterial is basically the same as that of a light-emitting element usinga low molecular weight organic luminescent material, which is alaminated structure of a cathode, a light-emitting laminated body, andan anode. However, it is difficult to form such a laminated structure asin the case of using a low molecular weight organic luminescent materialwhen a light-emitting laminated body using a high molecular weightorganic luminescent material is formed. Therefore, a two-layer structureis employed in many cases. Specifically, a laminated structure of acathode, a light-emitting layer, a hole transporting layer, and an anodeis employed.

The luminescent color is determined by the material forming alight-emitting layer of the light-emitting laminated body. Therefore, alight-emitting element that emits desired light can be formed byselecting an appropriate material for the light-emitting laminated body.High molecular weight electroluminescent material that can be used toform the light-emitting layer include polyparaphenylenevinylenematerials, polyparaphenylene materials, polythiophen materials, andpolyfluorene materials.

The polyparaphenylenevinylene materials include derivatives ofpoly(paraphenylene vinylene) [PPV], poly(2,5-dialkoxy-1,4-phenylenevinylene) [RO-PPV], poly(2-(2′-ethyl-hexoxy)-5-metoxy-1,4-phenylenevinylene) [MEH-PPV], and poly(2-(dialkoxyphenyl)-1,4-phenylene vinylene)[ROPh-PPV]. The polyparaphenylene materials include derivatives ofpolyparaphenylene [PPP], poly(2,5-dialkoxy-1,4-phenylene) [RO-PPP] andpoly(2,5-dihexoxy-1,4-phenylene). The polythiophene materials includederivatives of polythiophene [PT], poly(3-alkylthiophene) [PAT],poly(3-hexylthiophene) [PHT], poly(3-cyclohexylthiophene) [PCHT],poly(3-cyclohexyl-4-methylthiophene) [PCHMT],poly(3,4-dicyclohexylthiophene) [PDCHT], poly[3-(4-octylphenyl)-thiophene] [POPT], and poly[3-(4-octylphenyl)-2,2bithiophene] [PTOPT]. The polyfluorene materials include derivatives ofpolyfluorene [PF], poly(9,9-dialkylfluorene) [PDAF] andpoly(9,9-dioctylfluorene) [PDOF].

Further, a high molecular weight organic luminescent material havinghole-transporting property is formed to be interposed between an anodeand a high molecular weight organic luminescent material, the holeinjection property from the anode can be enhanced. This high molecularweight organic luminescent material having hole-transporting property isgenerally dissolved into water together with an acceptor material, andthe solution is applied by spin coating or the like. Since the holetransporting material is insoluble in an organic solvent, the highmolecular weight organic luminescent material having hole-transportingproperty and the organic luminescent material described above can belaminated. The high molecular weight organic luminescent materialshaving hole-transporting property includes a mixture of PEDOT andcamphorsulfonic acid (CSA) that serves as an acceptor material, amixture of polyaniline [PANT] and polystyrene sulfonic acid [PSS] thatserves as an acceptor material, and the like.

In addition, the light-emitting layer can be formed to emitmonochromatic or white light. In the case of using a white luminescentmaterial, it makes color display possible to provide a filter (coloringlayer) through which light of a specific wavelength is transmitted onthe side to which light is emitted in a pixel.

In order to form a light-emitting layer that emits white light, forexample, Alq₃, Alq₃ partially doped with Nile red that is a redluminescent dye, Alq₃, p-EtTAZ, and TPD (aromatic diamine) aresequentially laminated by evaporation so that white light can beobtained. When a light emitting layer is formed by an application methodusing spin coating, it is preferable after the application to performbaking by vacuum heating. For example, an aqueous solution ofpoly(ethylene dioxythiophene)/poly(styrene sulfonic acid) (PEDOT/PSS)may be entirely applied and baked to act as a hole injecting layer, andthen, a polyvinyl carbazole (PVK) solution doped with a luminescentcenter dye (such as 1,1,4,4-tetraphenyl-1,3-butadiene (TPB),4-dicyanomethylene-2-methyl-6-(p-dimethylamino-styryl)-4H-pyran (DCM1),Nile red, or coumarin 6) may be entirely applied and baked to act as alight-emitting layer.

The light-emitting laminated body can be formed to be a single layer.For example, an electron transporting 1,3,4-oxadiazole derivative (PBD)may be dispersed in a hole transporting polyvinyl carbazole (PVK). Inaddition, white light emission can be obtained by dispersing 30 wt % PBDas an electron transporting agent and appropriately dispersing four dyes(TPB, coumarin 6, DCM1, and Nile red). In addition to the light-emittingelements described here, which provide white light emission, alight-emitting element that provides red light emission, green lightemission, or blue light emission can be manufactured by selecting thematerial for the light-emitting layer appropriately.

Further, a high molecular weight organic luminescent material havinghole-transporting property is formed to be interposed between an anodeand a high molecular weight organic luminescent material, the holeinjection property from the anode can be enhanced. This high molecularweight organic luminescent material having hole-transporting property isgenerally dissolved into water together with an acceptor material, andthe solution is applied by spin coating or the like. Since the holetransporting material is insoluble in an organic solvent, the highmolecular weight organic luminescent material having hole-transportingproperty and the organic luminescent material described above can belaminated. The high molecular weight organic luminescent materialshaving hole-transporting property includes a mixture of PEDOT andcamphorsulfonic acid (CSA) that serves as an acceptor material, amixture of polyaniline [PANT] and polystyrene sulfonic acid [PSS] thatserves as an acceptor material, and the like.

For the light-emitting layer, triplet-excitation luminescent materialssuch as metal complexes may be used in addition to singlet-excitationluminescent materials. For example, of a red light-emitting pixel, agreen light-emitting pixel, and a blue light-emitting pixel, the redlight-emitting pixel, which produces a luminance with a relatively shorthalf life in, is formed with the use of a triplet-excitation luminescentmaterial while the others are formed with the use of singlet-excitationluminescent materials. Since triplet-excitation luminescent materialsare excellent in luminous efficiency, it is a feature that lower powerconsumption is necessary to obtain the same luminance. Namely, when atriplet-excitation luminescent material is applied to the red pixel, thenecessary amount of the current applied to a light-emitting element islower so that the reliability can be improved. In order to lower powerconsumption, the red light-emitting pixel and the green light-emittingpixel may be formed with the use of triplet-excitation luminescentmaterials while the blue light-emitting pixel is formed with the use ofa singlet-excitation luminescent material. Also as for a greenlight-emitting element for which people have higher visibility acuity,the power consumption can be lowered by forming the green light-emittingelement with the use of a triplet-excitation luminescent material.

As an example of the triplet excitation light-emitting material, thereis a material using a metal complex as a dopant, and for example, ametal complex having platinum that is a third transition series elementas a central metal and a metal complex having iridium as a central metalare known. The triplet-excitation luminescent material is not limited tothese compounds, and a compound that has the structure described aboveand an element belonging to one of Groups 8 to 10 of the periodic tableas a central metal can also be used.

The above-described materials for forming a light-emitting layer arejust example. A light-emitting element can be formed by appropriatelystacking respective functional layers such as a hole injecting layer, ahole transporting layer, an electron injecting layer, an electrontransporting layer, a light-emitting layer, an electron blocking layer,and a hole blocking layer. Alternatively, a mixed layer or mixedjunction in which some of these respective layers are combined may beformed. The structure of the light-emitting laminated body can bechanged, and modifications can be permitted unless such changes andmodifications depart from the scope of the present invention. Forexample, instead of providing a specific electron injecting region orlight-emitting region, an electrode can be provided mainly for thispurpose, and a luminescent material can be provided by dispersing theluminescent material.

When the light-emitting element is biased in a forward direction, lightis emitted. Pixels of a display device formed with the use of thelight-emitting element can be driven by a simple matrix method or anactive matrix method. In any case, a forward bias is applied to eachpixel at a specific time to emit light while the pixel is in anon-emitting state for a certain period. When the reverse bias isapplied for this non-emitting time, the reliability of thelight-emitting element can be improved. In a light-emitting element,deterioration occurs, in which emission intensity is decreased underspecific driving conditions or a non-light-emitting region is enlargedin a pixel to decrease luminance apparently. However, progression ofdeterioration can be made slower by alternating driving in which aforward bias and a reverse bias are applied, and, the reliability of alight-emitting device can be thus improved.

Embodiment 1

FIG. 12A shown as Example 1 shows an emitting state photographed afterpreserving a light-emitting device according to the present invention,which has the structure shown in FIG. 1A and a desiccant provided at theopposed substrate 109, for 180 hours under conditions where the roomtemperature is 65° C. and the humidity is 95%. In addition, for FIG. 12Bshown as Comparative Example 1, although almost the same structure asthe structure for FIG. 12A is employed, there is a difference in thatthe wiring 103 in FIG. 1A extends under the upper electrode 107 for thelight-emitting element.

In FIGS. 12A and 12B, each of patterns arranged in a matrix represents apixel emitting light, and a pixel emitting no light is photographed inblack. The photographs are taken without being irradiated with lightwhile keeping all of the pixels driven to emit light.

It is determined that periphery deterioration progresses with disarrayof the patterns of the pixels in a periphery portion in FIG. 12B wherethe wiring 103 extends under the upper electrode 107 for thelight-emitting element while no periphery deterioration occurs withoutdisarray of the patterns in FIG. 12A to which the present invention isapplied. Thus, the utility of the present invention is recognized.

It is to be noted that glass substrates are used as the substrate 100and the opposed substrate 109, a silicon nitride film containing oxygenis used as the base insulating film 101, acrylic is used for the firstand second organic insulating films 102 and 105, a laminated body of Ti,Al—Si, and Al is used as the wiring 103, and a ultraviolet curable epoxyresin is used for the sealing material 108 in the example and thecomparative example.

In addition, the whole of the light-emitting device is not photographed,but a portion that has the structure according to the present inventionis selected while centering on the substrate edge, enlarged, and thenphotographed for the pictures in FIGS. 12A and 12B. However, thepositions photographed in Embodiment 1 and Comparative Example 1 areapproximately conformed to each other.

Embodiment 2

FIGS. 13A to 13C shown as Example 2 show emitting states photographedafter light-emitting devices according to the present invention, whichhave the structure shown in FIG. 1B and a desiccant provided at theopposed substrate 109, are preserved for 200 hours under conditionswhere the room temperature is 65° C. and the humidity is 95%. In FIGS.13A to 13C, there are respectively gaps (corresponding to the gap b inFIG. 1B) of 200 μm, 50 μm, and 20 μm between the wirings 103 a and 103b, and the wiring 103 b extends to under the upper electrode 107 for thelight-emitting element. FIG. 13D that is Comparative Example 2 has astructure in which the gap between the wiring 103 a and 103 b is 0 μm,that is, a structure without the gap or a structure in which the wiring103 a extends under the upper electrode 107.

In FIGS. 13A to 13D, each of patterns arranged in a matrix represents apixel emitting light, and each of the photographs arranged at the uppercolumn in the figures is a photograph taken by irradiating a sample withlight and observing light reflected at the sample while each of thephotographs arranged at the lower column in the figures is a photographtaken without being irradiated with light. The shapes of the wirings canbe confirmed in the photographs at the upper column, and the pixelsemitting light can be confirmed in the photographs at the lower columnsince the pixels emitting no light are photographed in black. It is tobe noted that the upper and lower photographs in each of FIGS. 13A to13D have the same position photographed and that each of the photographsis taken while keeping all of the pixels driven to emit light.

The result is that loss of light emission due to deterioration is notrecognized in the structure of each of FIGS. 13A to 13C, where the gapis provided between the wirings 103 a and 103 b as described above,while periphery deterioration progresses so much under the sameconditions that there is no lighted pixel in the observed area inComparative Example 2. Thus, the utility of the present invention isrecognized. It is to be noted that it is preferable that the gaps arethe 1 μm or more, preferably 10 or more, and more preferably 20 μm ormore.

It is to be noted that glass substrates are used as the substrate 100and the opposed substrate 109, a silicon nitride film containing oxygenis used as the base insulating film 101, acrylic is used for the firstand second organic insulating films 102 and 105, a laminated body of Ti,Al—Si, and Al is used as the wiring 103, and a ultraviolet curable epoxyresin is used for the sealing material 108 in the example and thecomparative example.

Embodiment 3

FIGS. 14A and 14B shown as Example 3 show emitting states photographedafter light-emitting devices according to the present invention, whichhave the structure shown in FIGS. 2A to 2C and a desiccant provided atthe opposed substrate 109, are preserved for 84 hours under conditionswhere the room temperature is 65° C. and the humidity is 95%. In FIG.14A, a wiring (corresponding to the wiring 103 in FIG. 2C) that has awidth (corresponding to the width c in FIG. 2C) of 5 μm and a wiringthat has a width of 20 μm can be observed, and a wiring that has a widthof 100 μm can be observed in FIG. 14B.

In FIGS. 14A to 14E, each of patterns arranged in a matrix represents apixel emitting light, and each of the photographs arranged at the uppercolumn in the figures is a photograph taken by irradiating a sample withlight and observing light reflected at the sample while each of thephotographs arranged at the lower column in the figures is a photographtaken without being irradiated with light. The shapes of the wirings canbe confirmed in the photographs at the upper column, and the pixelsemitting light can be confirmed in the photographs at the lower columnsince the pixels emitting no light are photographed in black. It is tobe noted that the upper and lower photographs in each of FIGS. 13A to13D have the same position photographed and that each of the photographsis taken light while keeping all of the pixels driven to emit light.

In FIGS. 14C to 14E shown as Comparative Example 3, wirings that havewidths of 1 mm, 5 mm, and 10 mm are formed respectively. It is to benoted that only pixels appear in the photographs in FIGS. 14D and 14Ebecause the wiring with the width of 5 mm or more is too large to beincluded in the photograph. The result is that no deterioration occursin FIGS. 14A and 14B with the width of the wiring: 5 μm, 20 μm, and 100μm with the structure according to the present invention whiledeterioration occurs since the width of the wiring is increased inComparative Example 3 (the width of the wiring: 1 mm, 5 mm, and 10 mm).Thus, the utility of the present invention is recognized.

It is to be noted that glass substrates are used as the substrate 100and the opposed substrate 109, a silicon nitride film containing oxygenis used as the base insulating film 101, acrylic is used for the firstand second organic insulating films 102 and 105, a laminated layer ofTi, Al—Si, and Al is used as the wiring 103, and a ultraviolet curableepoxy resin is used for the sealing material 108 in the example and thecomparative example.

Embodiment 4

FIGS. 15A to 15D shown as Example 4 show emitting states photographedafter preserving light-emitting devices according to the presentinvention, which have the structure shown in FIGS. 3A to 3C and adesiccant provided at the opposed substrate 109, for 200 hours underconditions where the room temperature is 65° C. and the humidity is 95%.In FIGS. 15A to 15D, wirings (corresponding to the wirings 103 in FIG.3C) that have a width (corresponding to the width c in FIG. 3C) of 30 μmare arranged apart from each other, where the distances (correspondingto the distance d in FIG. 3C) between the wirings are respectively 20μm, 15 μm, 10 μm, and 5 μm.

In FIGS. 15A to 15D, each of patterns arranged in a matrix represents apixel emitting light, and each of the photographs arranged at the uppercolumn in the figures is a photograph taken by irradiating a sample withlight and observing light reflected at the sample while each of thephotographs arranged at the lower column in the FIG. is a photographtaken without being irradiated with light. The shapes of the wirings canbe confirmed in the photographs at the upper column, and the pixelsemitting light can be confirmed in the photographs at the lower columnsince the pixels emitting no light are photographed in black. It is tobe noted that the upper and lower photographs in each of FIGS. 13A to13D have the same position photographed and that each of the photographsis taken light while keeping all of the pixels driven to emit light.

A comparative example in which the distance is 0 μm corresponds toComparative Example 2 shown in Embodiment 2. The result is that nodeterioration occurs in Embodiment 4 with the structure shown in FIGS.3A to 3C while deterioration occurs after a preservation test for thesame hours under the same conditions in Comparative Example 2. Thus, theutility of the present invention is recognized.

It is to be noted that glass substrates are used as the substrate 100and the opposed substrate 109, a silicon nitride film containing oxygenis used as the base insulating film 101, acrylic is used for the firstand second organic insulating films 102 and 105, a laminated layer ofTi, Al—Si, and Al is used as the wiring 103, and a ultraviolet curableepoxy resin is used for the sealing material 108 in the example and thecomparative example.

Embodiment 5

FIG. 16A shown as Example 5 shows an emitting state of a light-emittingdevice according to the present invention, which has the structure shownin FIG. 1B at a top portion, a left portion, and a bottom portion in thephotograph and has a structure that is similar to the structure shown inFIGS. 4A to 4C at a right portion in the photograph, and photographedafter the light emitting device is preserved for 30 hours underconditions where the room temperature is 65° C. and the humidity is 95%.Further, a desiccant is provided at the opposed substrate 109.

FIG. 17 shows a schematic view showing a wiring pattern, a sealingpattern, an electrode pattern for a light-emitting element, and the likein the light emitting device of FIG. 16A. Reference numeral 301corresponds to a gap of 20 μm, and reference numeral 300 denotes astructure in which a plurality of openings that have shorter side ofapproximately 5 mm are arranged approximately 100 mm apart from eachother to be adjacent to each other in the narrower-side direction of theopening.

In addition, FIG. 16B shown as Comparative Example 5 is a photographafter preserving a light-emitting device to which the measure describedabove is not applied for the same hours under the same conditions. Eachof patterns arranged in a matrix represents a pixel emitting light, anda pixel emitting no light is photographed in black. The photographs aretaken without being irradiated with light while keeping all of thepixels driven to emit light.

The result is that periphery deterioration progresses in FIG. 16B towhich the present invention is not applied while no peripherydeterioration occurs in FIG. 16A to which the present invention isapplied. Thus, the utility of the present invention is recognized.

It is to be noted that glass substrates are used as the substrate 100and the opposed substrate 109, a silicon nitride film containing oxygenis used as the base insulating film 101, siloxane is used for the firstorganic insulating film 102, polyimide is used for the second organicinsulating film 105, a laminated layer of Ti, Al—Si, and Al is used asthe wiring 103, and a ultraviolet curable epoxy resin is used for thesealing material 108 in the present embodiment and comparative example.

In addition, the whole of the light-emitting device is not photographed,but a portion that has the structure according to the present inventionis selected while centering on the substrate edge, enlarged, and thenphotographed for the pictures in FIGS. 12A and 12B. However, thepositions photographed in Embodiment 1 and Comparative Example 1 areapproximately conformed to each other.

Although the present invention has been fully described by way ofexample with reference to the accompanying drawings, it is to beunderstood that various changes and modifications will be apparent tothose skilled in the art. Therefore, unless such changes andmodifications depart from the scope of the present invention hereinafterdefined, they should be construed as being included therein.

What is claimed is:
 1. A light-emitting device comprising: a firstorganic insulating layer over a first substrate; a conductive layer overthe first organic insulating layer; an anode over the first organicinsulating layer; a second organic insulating layer over the conductivelayer and the anode; a layer containing a light-emitting material overthe second organic insulating layer; a cathode over the layer containinga light-emitting material; a second substrate over the cathode; and alayer configured to keep a gap between the first substrate and thesecond substrate, wherein the cathode overlaps a first region of theconductive layer with the second organic insulating layer therebetween,wherein the layer configured to keep a gap between the first substrateand the second substrate overlaps the conductive layer with the secondorganic insulating layer therebetween, and wherein the conductive layercomprises a plurality of openings in a second region which is notoverlapped by the cathode.
 2. The light-emitting device according toclaim 1, wherein the cathode overlaps with a gap between the conductivelayer and the anode.
 3. The light-emitting device according to claim 1,wherein the cathode comprises a region which does not overlap the layercontaining a light-emitting material.
 4. A light-emitting devicecomprising: a first organic insulating layer over a first substrate; aconductive layer over the first organic insulating layer; an anode overthe first organic insulating layer; a second organic insulating layerover the conductive layer and the anode; a layer containing alight-emitting material over the second organic insulating layer; acathode over the layer containing a light-emitting material; a secondsubstrate over the cathode; and a layer configured to keep a gap betweenthe first substrate and the second substrate, wherein the cathodeoverlaps a first region of the conductive layer with the second organicinsulating layer therebetween, wherein the layer configured to keep agap between the first substrate and the second substrate overlaps theconductive layer with the second organic insulating layer therebetween,wherein the conductive layer comprises a plurality of openings in asecond region which is not overlapped by the cathode, and wherein thelayer configured to keep a gap between the first substrate and thesecond substrate overlaps the plurality of openings.
 5. Thelight-emitting device according to claim 4, wherein the cathode overlapswith a gap between the conductive layer and the anode.
 6. Thelight-emitting device according to claim 4, wherein the cathodecomprises a region which does not overlap the layer containing alight-emitting material.
 7. A light-emitting device comprising: a firstorganic insulating layer over a first substrate; a conductive layer overthe first organic insulating layer; an anode over the first organicinsulating layer; a second organic insulating layer over the conductivelayer and the anode; a layer containing a light-emitting material overthe second organic insulating layer; a cathode over the layer containinga light-emitting material; a second substrate over the cathode; and alayer configured to keep a gap between the first substrate and thesecond substrate, wherein the cathode overlaps a first region of theconductive layer with the second organic insulating layer therebetween,wherein the layer configured to keep a gap between the first substrateand the second substrate overlaps the conductive layer with the secondorganic insulating layer therebetween, wherein the conductive layercomprises a plurality of openings in a second region which is notoverlapped by the cathode, and wherein the conductive layer is spacedfrom the anode.
 8. The light-emitting device according to claim 7,wherein the cathode overlaps with a gap between the conductive layer andthe anode.
 9. The light-emitting device according to claim 7, whereinthe cathode comprises a region which does not overlap the layercontaining a light-emitting material.
 10. A light-emitting devicecomprising: a first organic insulating layer over a first substrate; aconductive layer over the first organic insulating layer; an anode overthe first organic insulating layer; a second organic insulating layerover the conductive layer and the anode; a layer containing alight-emitting material over the second organic insulating layer; acathode over the layer containing a light-emitting material; a secondsubstrate over the cathode; and a layer configured to keep a gap betweenthe first substrate and the second substrate, wherein the cathodeoverlaps a first region of the conductive layer with the second organicinsulating layer therebetween, wherein the layer configured to keep agap between the first substrate and the second substrate overlaps theconductive layer with the second organic insulating layer therebetween,wherein the conductive layer comprises a plurality of openings in asecond region which is not overlapped by the cathode, wherein the layerconfigured to keep a gap between the first substrate and the secondsubstrate overlaps the plurality of openings, and wherein the conductivelayer is spaced from the anode.
 11. The light-emitting device accordingto claim 10, wherein the cathode overlaps with a gap between theconductive layer and the anode.
 12. The light-emitting device accordingto claim 10, wherein the cathode comprises a region which does notoverlap the layer containing a light-emitting material.